Feeding device having a double-disk feed having a separated drive and method for operating such a feeding device

ABSTRACT

A feeding device for an in-line screw machine with a shaft rotating in a feed container. A conveying screw is arranged in the direction toward the longitudinal axis of the rotating shaft. At least one disk wheel is allocated to each longitudinal side in the feed container. A separate drive is allocated to each disk wheel for purposes of rotational movement.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of pending Internationalpatent application PCT/DE2010/000556 filed on May 18, 2010 whichdesignates the United States and claims priority from German patentapplication 20 2009 010 131.2 filed on Jul. 24, 2009, the content ofwhich is incorporated herein by reference.

FIELD OF THE INVENTION

The invention relates to feeding devices for in-line screw machines witha shaft rotating in a feed container. The shaft exhibits a screw-shapedtransport means that conveys in the direction toward the longitudinalaxis of the shaft, and is not mechanically linked with a feed aid.

BACKGROUND OF THE INVENTION

German patent specification DE 10 2008 020 41 B3 relates to a feedingdevice for in-line screw machines, in particular to avoid bridging inthe medium to be conveyed. Generating unsymmetrical shear forces onopposing sides of the conveyor screw avoids the formation of textures inthe medium that lead to bridging. This is realized by two disk wheels,which are driven by the conveyor screw. In addition, the disk wheels areequipped with strips that recirculate and/or loosen any material thatmight have dammed up in the feeding device.

Design patent DE 298 08 800 U1 discloses a feeding device for screwconveyors. In this configuration, the screw conveyor simultaneouslyserves as the drive for the catch element of the feeding device. Thefive depicted catch elements join together two wheels, the bearings ofwhich are arranged on the same rotational axis. Since the catch elementsengage into the screw flights, the feeding device rotates as soon as theconveyor screw operates. The advantage to this arrangement is that itrequires no additional drive for the feeding device. However, there islittle avoidance of the bridging expected to arise when conveying heavyconveying media.

The German translation DE 35 86 241 T2 of European patent specificationEP 0 185 541 B1 describes a screw conveyor, in which two parallel,spaced apart conveyor screws rotate in a housing. To improve the way theproduct to be conveyed gets into or between the screw flights, draw-inrollers with wings are provided, arranged either one perpendicular ortwo parallel to the conveyor screws. The draw-in rollers with theirmovable wings that engage into the product are situated above theconveyor screws, and to the side of the latter in the dualconfiguration, and made to rotate independently of the conveyor screwsof separate drives.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a feeding device withwhich bridging can be avoided, in particular when conveying heavyconveying media.

The object of the invention is achieved with the features in claim 1,wherein advantageous features to avoid bridging may be gleaned from thesubclaims.

The object of the invention is further to create a method with which afeeding device for heavy conveying media can be smoothly andeconomically operated.

This object is achieved by a method for operating the feeding device,characterized by the following points: each disk wheel is separatelypowered; the disk wheels move and/or loosen a compacted conveying mediumin the feed container; and the disk wheels are rotated against or in theconveying direction of a screw.

The feeding device for in-line screw machines according to the inventionis provided with a shaft that rotates in a feed container. A conveyorscrew is arranged in the direction toward the longitudinal axis of therotating shaft. At least one disk wheel is allocated to the feedcontainer on each longitudinal side, wherein each disk wheel is equippedwith a separate drive. In order to prevent bridging of compactedconveying media in the feed container, the disk wheels can rotate.

In order to again release the compacted conveying medium between thedisk wheels, the two opposing disk wheels are operated at varyingspeeds. This difference in speed produces a shearing action whilerecirculating the conveying medium located between the disk wheels. Thisloosens the compacted material during recirculation.

The opposing sides of the disk wheels are provided with a structuredsurface. In another preferred embodiment, both sides of the disk wheelexhibit structured surfaces. Imparting a structured surface to bothsides of the disk wheels allows both sides to be used. If the structuredsurface of one side of the disk wheel is worn, the disk wheel can beturned and used from the other side. This configuration makes itpossible to save on disk material, and reduce storage costs forreplacement disk wheels.

The structured surface of the disk wheels makes it possible to transportthe compacted conveying medium in the feed container. The compactedconveying medium is lifted between the disk wheels, and released againat a defined point in the feed container. Transport takes place as aresult of the interaction between the conveying medium and disk wheelscaused by the structured surface.

Depending on the configuration of the in-line screw machines, it may benecessary to arrange several disk wheels on each longitudinal side ofthe feed container. In addition, the disk wheels can be offset in thelongitudinal direction relative to the axial longitudinal axis of therotating shaft. Offsetting the disk wheels in this way causes the diskwheels to move synchronously to each other only within a specific range,and release the compacted conveying medium at locations where there isno overlap.

The disk wheels can be rotated in or against the conveying direction ofthe screw. In order to destroy compacted conveying medium bridgeswithout transporting the conveying media in the feed container, the diskwheels can be powered in opposite directions.

The disk wheels are connected with an axis by means of at least twospokes. The disk wheels can each be powered by a separate drive via theaxis. In addition, the spokes of the disk wheels are also provided witha structured surface.

The method according to the invention for operating a feeding device isbased on separately powering each disk wheel. The compacted conveyingmedium in the feed container is transported or recirculated via astructured surface of the disk wheels. This avoids bridging and/ordestroys existing bridges. The disk wheels are rotated in or against theconveying direction of a screw. Release of the compacted conveyingmedium is assisted by the difference in speeds of the two opposing diskwheels. In another embodiment, the disk wheels are powered in oppositedirections, so that bridging in the feed container can be avoided. Inaddition, the basic speed and differential speed can be adjusted to thespecial requirements of the respective conveying medium.

Exemplary embodiments of the invention and their advantages will bedescribed in greater detail below based on the attached figures. Thedimensional ratios between the individual elements on the figures do notalways correspond to the actual dimensional ratios, since several shapesare simplified, and other shapes have been magnified in relation toother elements by way of illustration.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a diagrammatic view of the structural design of the feedingdevice according to the invention.

FIG. 2 shows different directions of movement for the disk motors.

FIG. 3 shows the diagrammatic structural design of a disk wheel withstructured surface in a preferred embodiment.

DETAILED DESCRIPTION OF THE INVENTION

The same reference numbers are used for elements of the invention thatare identical or have an identical effect. In addition, for the sake ofclarity, the individual figures present only reference numbers requiredfor describing the respective figure.

FIG. 1 shows a diagrammatic view of the structural design of the feedingdevice 20 according to the invention. The first disk wheel 40 and seconddisk wheel 42 are situated inside the feed container 30 on thelongitudinal sides 24 and 26. A first drive 44 is allocated to the firstdisk wheel 40, and a second drive 46 is allocated to the second diskwheel 42. As a result of the two drives 44 and 46, the two disk wheels40 and 42 are independent of each other, and can be powered so as toseparately rotate. An in-line screw machine 22 is arranged in thelongitudinal direction of the feed container 30. Situated inside thein-line screw machine 22 is a shaft 32, on which a conveyor screw 34 issecured. The shaft 32 runs along a longitudinal axis 31.

FIG. 2 shows different directions of movement 50 and 52 for the diskwheels 40 and 42 by way of rotational direction arrows. The conveyingdirection 36 of the in-line screw machine 22 also runs along thelongitudinal axis 31. The disk wheels 40 and 42 can be moved in a firstdirection of movement 50 in the conveying direction 36, or in a seconddirection of movement 52 against the conveying direction 36. Inaddition, it is conceivable to rotate the first disk wheel 40 in thefirst direction of movement 50 and the second disk wheel 42 in thesecond direction of movement 52, for example.

FIG. 3 shows the diagrammatic structural design of a disk wheel 40 withstructured surface 48 in a preferred embodiment. The disk wheel 40consists of a disk rim 54 and several spokes 56. The spokes 56 runoutwardly from one axis 58 toward the disk rim 56. The disk wheel 40 isconnected with a shaft 60 by several attachment points 62. This shaft 60runs along the axis 58. The disk rim 56 and/or spokes 56 are providedwith a structured surface 48. Each disk wheel 40 is radially moved by aseparate drive (not shown) via the axis 58.

The invention was described with reference to a preferred embodiment.However, an expert can conceivably modify or change the inventionwithout departing from the protective scope of the following claims.

1. A feeding device for in-line screw machines with a shaft that rotatesin a feed container and exhibits a screw that conveys in the directiontoward the longitudinal axis of the rotating shaft, wherein at least onedisk wheel is allocated to each longitudinal side in the feed container,characterized in that each disk wheel can be rotated with at least oneseparate drive.
 2. The feeding device according to claim 1,characterized in that the disk wheels can be moved at different speeds.3. The feeding device according to claim 1, characterized in that theopposing sides of the disk wheels are provided with a structuredsurface.
 4. The feeding device according to claim 3, characterized inthat both sides of the disk wheels are provided with a structuredsurface.
 5. The feeding device according to claim 1, characterized inthat the disk wheels can move and/or loosen a compacted conveying mediumin the feed container.
 6. The feeding device according to claim 1,characterized in that several disk wheels are arranged on eachlongitudinal side.
 7. The feeding device according to claim 1,characterized in that the disk wheels are offset axially to thelongitudinal axis of the rotating shaft.
 8. The feeding device accordingto claim 1, characterized in that the disk wheels can be rotated againstor in the conveying direction of the screw.
 9. The feeding deviceaccording to claim 1, characterized in that the disk wheels can bepowered in opposite directions.
 10. The feeding device according toclaim 1, characterized in that the disk wheels are connected with anaxis by means of at least two spokes.
 11. The feeding device accordingto claim 10, characterized in that the spokes are provided with astructured surface.
 12. A method for operating a feeding device forin-line screw machines with a shaft that rotates in a feed container andexhibits a screw that conveys in the direction toward the longitudinalaxis of the rotating shaft, wherein at least one disk wheel is allocatedto each longitudinal side in the feed container and each disk wheel canbe rotated with at least one separate drive, characterized by thefollowing points: Each disk wheel is separately powered; The disk wheelsmove and/or loosen a compacted conveying medium in the feed container;and The disk wheels are rotated against or in the conveying direction ofa screw.
 13. A method for operating a feeding device according to claim12, characterized in that the disk wheels are moved at different speeds.14. A method for operating a feeding device according to claim 12,characterized in that the disk wheels are powered in oppositedirections.